Integumentary enclosure for video equipment

ABSTRACT

A waterproof integumentary enclosure for electronic equipment, especially video cameras, is comprised of a thin transparent skin or membrane which enables submerged use of the equipment, provides a barrier to damaging water and particulate matter and simultaneously permits uninhibited access to and operation of audio, video and infra-red components of the equipment. The apparatus is comprised of three primary components including the integument, a support platform upon which the equipment is secured, and a combination air extraction and membrane closure means. The latter is comprised generally of an elongated tubular shaft rotatably mounted to the support platform. In operation, the shaft is rotated about the platform causing the membrane within to twist and seal itself about the exterior walls of an air evacuation tube. Air within the system is then withdrawn either manually or mechanically causing the membrane to collapse around and closely conform to the video equipment thereby forming the integumentary barrier. A closure apparatus is provided to seal the system and a secondary sealing apparatus is provided. An optional lens adapter is also included to provide a flat surface against which the optical membrane can rest to avoid distortion thereof when exposed to sub-atmospheric pressure when the camera is submerged. The lens adapter is also designed to prevent condensation which might occur upon exposure of the system to temperature differences between air and water.

FIELD OF THE INVENTION

The subject invention relates to protective coverings for videoequipment in general, and to a system for enclosing said equipment in adisposable, water-tight integument, in particular.

BACKGROUND OF THE INVENTION

Heretofore, a variety of devices have been employed to adaptconventional cameras and video cameras for underwater use. Still otherdevices have been developed which, to some extent, enable suchelectronic equipment to be used in inclement weather conditions or inenvironments otherwise hostile to the equipment such as the beach, forexample. The subject invention provides a means for accomplishing eachof these ends.

A review of the prior art reveals two general categories ofwaterproofing devices within which electronic equipment may be placedfor protection. The first species share in common the employment of arigid pressure hull or chamber adapted with external controls which areconnected to and operate the camera held within the chamber. Suchdevices suffer from various shortcomings, namely they are bulky, overlycomplex in both structure and operation, and are cost prohibitive forthe amateur photographer and even some professionals.

These shortcomings associated with rigid equipment vessels resulted inthe development of the second species of protective devices which aregenerally comprised of a flexible bag-like enclosure with opticalwindows against which the camera's viewfinder and lens are to be placed.Such devices allow the user to operate the cameras controls through thesurrounding flexible bag which is typically fabricated of a clearplastic material to facilitate this purpose.

One of the earliest references relating to this latter species ofprotective device is U.S. Pat. No. 1,535,312 issued to Hosking in 1925which teaches a waterproof covering for cameras. The device consists ofa flexible waterproof bag-like covering having draw strings at thebottom thereof for closure purposes. One serious limitation of thisrelatively simplistic device is that it requires the user to keep thecamera upright when used underwater to prevent the entrance of waterthrough the bag opening. In one embodiment, the Hosking referenceteaches the use of a sash-like window against which the camera lense isplaced.

In 1962, U.S. Pat. No. 3,026,784 was issued to Byers for an underwaterphotography enclosure with the open end of the bag being sealed,allowing a volume of entrapped air to remain such that the apparatus asa whole could float for purposes which are obvious. Similarly, U.S. Pat.No. 3,042,796 issued to De Forest in 1962 teaches a bag closing meanssimilar to that disclosed in Byers and also teaches the entrapment ofair for buoyancy purposes. The problem with each of these references andbag-like enclosures generally, however, is that any significant amountof entrapped air between the camera and the bag will make it moredifficult to locate and operate the control buttons of the camera.

This problem was slightly corrected by U.S. Pat. Nos. 5,087,934 and5,239,323, each issued to Johnson in 1992 and 1993 respectively, whichteach a waterproof and flexible semi-rigid housing shaped to roughlyconform to the shape of the camera equipment contained therein. Byproviding a camera-shaped bag rather than a conventionally shaped one,the Johnson device reduced the amount of entrapped air within thesystem, however, the shape of the enclosure could not be universallyapplied to all video cameras which are of different sizes and shapes andwhich may have viewfinders in different locations.

Finally, U.S. Pat. No. 4,771,299 issued to Gell, Jr. in 1988 teaches theuse of a flexible waterproof container and a means of pressurizing thecontainer so that the equipment may be used at greater depths bypreventing the collapse of the flexible material and its molding aroundthe camera under pressure.

Each of the above described references share in common the entrapment ofair within the enclosure, whether incidentally as a result of theirconstruction, or intentionally for the purpose of pressurizing thesystem for buoyancy or use at greater depths. Applicant has discoveredthat the exact opposite characteristic is desirable, namely providing anenclosure system which is relatively devoid of air. By withdrawing airfrom the system before closure, applicant has discovered a means ofobviating those shortcomings associated with the prior art.

SUMMARY OF THE INVENTION

More particularly, the subject invention provides a waterproof enclosurefor electronic equipment, especially video cameras, in the form of athin transparent skin or membrane. This video equipment "integument" notonly forms a barrier to damaging water and particulate matter, but soclosely conforms to the shape of the underlying equipment as to berelatively unnoticeable during use. Accordingly, access to controlsremains unobstructed. Moreover, the subject invention may be applied toany shape video or camera equipment without interfering with the properperformance of audio, video and infra-red components of the equipment.

To this end the subject invention is comprised of three primarycomponents. The first primary component consists of an opticallytransparent membrane that is substantially flexible in nature andimpermeable to water and other fluids. The membrane is fabricated into abag-like configuration having a single open end for the reception of theelectronic equipment to be protected therein. The second primarycomponent consists of a horizontally oriented planer support platformupon which the equipment is secured for use. The third and final primarycomponent consists of a combination air extraction and membrane closuremeans which itself consists very generally of an elongated tubular shaftmember rotatably mounted to an aperture of slightly larger diameterlocated within the center of the support platform. A ratchet assembly isincluded in the platform-to-shaft connection such that the shaft iscapable of precise incremental rotation.

In operation, after the device to be protected is placed within theenclosure, the open end of the membrane is threaded through both theplatform's aperture and tubular shaft until it emerges from the terminalend of the shaft. The opening of the membrane is then folded upwardlyabout the exterior circumference of the shaft and secured in place withan end cap.

A thin air evacuation tube is inserted through an evacuation portlocated in the center of the end cap and into the shaft along theshaft's vertical axis. Thusly situated, the air evacuation tube isconcentrically oriented inside the shaft and more particularly insidethe membrane enclosure. The shaft is then rotated about the platformcausing the membrane within to twist and seal itself about the exteriorwalls of the extraction tube. Air within the system is then withdrawneither manually or mechanically causing the membrane to collapse aroundand closely conform to the video equipment thereby forming anintegumentary waterproof barrier. The evacuation tube is then withdrawnfrom the shaft whereupon the twisted portion of the membrane willcollapse around itself to maintain the airtight seal. Additionalrotation of the shaft may be performed to tighten the seal. Closuremeans are provided to seal the extraction port. As a final precaution,the shaft is adapted with a radially aligned compression screw whichupon tightening will force the twisted membrane against the interiorwall of the shaft to assure an airtight seal.

An optional lens adapter is also included to provide a flat surfaceagainst which the optical membrane can rest to avoid distortion thereofwhen exposed to sub-atmospheric pressure when the camera is submerged.The lens adapter is also designed to prevent condensation which mightoccur upon exposure of the system to temperature differences between airand water.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject matter of the claims appended hereto. Inthis respect, before explaining at least one embodiment of the inventionin detail, it is to be understood that the invention is not limited inits application to the details of construction and to the arrangementsof the components set forth in the following description or illustratedin the drawings. For instance, the subject invention may be used withmany different types of electronic equipment although video cameras areused as an example and illustrated in the drawings. The invention iscapable of other embodiments and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein are for the purpose of description andshould not be regarded as limiting. As such, those skilled in the artwill appreciate that the conception, upon which this disclosure isbased, may readily be utilized as a basis for the designing of otherstructures, methods and systems for carrying out the several purposes ofthe present invention. It is important, therefore, that the claims beregarded as including such equivalent constructions insofar as they donot depart from the spirit and scope of the present invention.

Further, the purpose of the foregoing abstract is to enable the U.S.Patent and Trademark Office and the public generally, and especially thescientists, engineers and practitioners in the art who are not familiarwith patent or legal terms or phraseology, to determine quickly from acursory inspection the nature and essence of the technical disclosure ofthe application. The abstract is neither intended to define theinvention of the application, which is measured by the claims, nor is itintended to be limiting as to the scope of the invention in any way.

It is, therefore, a primary object of the subject invention to provide awaterproof integumentary enclosure for electronic equipment, especiallyvideo cameras, by means of which said equipment may be used underwater.

It is also a primary object of the subject invention to provide awaterproof integumentary enclosure in the form of a thin, flexible andtransparent membrane which closely conforms to the shape of a variety ofdifferent video and still cameras as well as other electronic equipment.

It is also a primary object of the present invention to provide awaterproof integument for electronic equipment, said integumentproviding a means for uninhibited access to and operation of audio,video and infra-red components of the equipment.

Another object of the subject invention is to provide a waterproofintegument for electronic equipment; said invention being relativelysimple in its construction and therefore inexpensive to manufacture andpurchase.

It is also an object of the present invention to provide anintegumentary membrane capable of protecting electronic equipment fromrain, snow, moisture, sand, dirt and other particulate matter.

It is another object of the present invention to provide anintegumentary enclosure for electronic equipment; said enclosurerequiring no special training or difficult procedures to master forsuccessful use.

Still another object of the present invention is to provide anintegumentary enclosure for electronic equipment; said enclosure beingdisposable after each use, thereby insuring against future contaminationto protected equipment occuring from residual matter on the membrane.

Yet another object of the present invention is to provide anintegumentary enclosure for electronic equipment which, when packaged,is sufficiently small and compact to be carried in a camera bag,clothing pocket or otherwise readily accessible for use.

These together with other objects of the invention, along with thevarious features of novelty which characterize the invention, arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its advantages and the specific objects attained by its uses, referenceshould be had to the accompanying drawings and descriptive matter inwhich there is illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those setforth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawings wherein:

FIG. 1 is a plan view of the integumentary enclosure component of thesubject invention;

FIG. 2A is a side elevation of the electronic equipment support platformand air extraction means of the subject invention, varioussub-components of which are depicted in phantom line, cutaway orexploded view to better illustrate the interrelations thereof;

FIG. 2B is an enlarged view of ratchet assembly components as mountedwithin the air extraction and compression shaft collar of the subjectinvention;

FIG. 3 is a plan view of the platform component of the subjectapparatus;

FIG. 4A is a cross-sectional view of an optional camera lens adaptercomponent of the subject invention;

FIG. 4B is a plan view of a flanged contraction ring used to tightlyconform the integumentary membrane over the surface of the camera'slens; and

FIGS. 5-9 are side elevational views of the subject invention duringvarious stages of its application to a conventional video camera.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to FIG. 1 in which there is illustrated a planview of the first of the three primary components of the subjectinvention, namely the integumentary enclosure designated generally byreference numeral 10. As may readily be observed, integument 10 ismanufactured into a bag-like configuration having a single opening 12for the reception of the electronic equipment to be protected therein.This optically transparent membrane is substantially flexible in natureand impermeable to water and other fluids. Integument 10 may befabricated of a thermal plastic film of any suitable material such asacetates, acrylics, cellulose acetate butylates, polycarbonates,polystyrenes, vinyls or ionmers with polyvinyl being preferred.Thickness may vary from as little as 0.025 mm to a maximum thickness asdetermined by the material's ability to remain flexible and achieve itsintended objects as set forth above and below.

The open end of integumentary enclosure 10 is adapted with four guidewires 14, each extending perpendicularly from the enclosure's edge.Guide wires 14 are fixedly attached to enclosure 10 using an appropriateadhesive tape 20 or by other suitable means. The enclosure is alsomodified with a color identification band 16 around its entireperimeter. Band 16 may be observed to run in parallel with perforation18 which, in turn, is situate approximately one inch above theenclosure's edge 19. Perforation 18 permits detachment of theenclosure's distal end 10A from the main body 10B. The functionality ofeach of these features is explained below.

Referring now to FIG. 2A, the remaining two primary components of thesubject invention are depicted in phantom line, cutaway or exploded viewto better illustrate how the sub-components thereof interrelate. Thesecond primary component is comprised of a rectangular support platform22 upon which the equipment is secured for use. For illustrativepurposes only, a video camera 100 is depicted as the equipment to beprotected. It should readily be understood, however, that said cameradoes not form a part of the subject invention.

Front, back and side retaining walls 24 may be fixedly mounted to thetop surface 26 of platform 22 to limit movement of the equipment onsurface 26. Both platform 22 and retaining walls 24 are preferably madeof a closed-cell foam product which is generally soft, durable andbuoyant. Platform 22 is further adapted with aperture 28, shown inphantom lines, disposed through the platform's center. A plan view ofplatform 22 is provided at FIG. 3.

With continued reference to FIG. 1, the third and final primarycomponent is illustrated and consists of a combination air extractionand membrane closure means 30 which itself is comprised very generallyof an elongated tubular shaft member 32 rotatably mounted to platform 22via shaft-to-platform adaptor 34. To accomplish the connection, annularring 36 of adaptor 34 is inserted into aperture 28 and fixedly attachedusing conventional means. The respective diameters of aperture 28 andring 36 are such as to form a snug, air-tight fit.

The proximal end 38 of shaft 32 is fitted with annular collar 40. Thedistal end 42 of adaptor 34 and the interior surface of collar 40 arereciprocally threaded to accomplish the rotatable connection of shaft 32to platform 22. Adaptor 34 and shaft 32 are each adapted with componentsof a ratchet assembly to permit precise incremental rotation of shaft 32relative to platform 22. More particularly, adaptor 34 is modified witha plurality of incrementally spaced ratchet teeth 44 situate betweenring 36 and distal end 42. A ratchet pin 46 is disposed through theflanged portion of collar 40 as more easily observed upon reference toFIG. 2B. Pin 46 terminates at one end with ratchet release handle 48 andat the opposite end with ratchet head 50. As shaft 32 is screwed ontoadaptor 34, ratchet head 50 is caused to engage ratchet teeth 44 therebycreating incremental, non-reversible movement of the shaft. Ratchet head50 is biased against ratchet teeth 44 through the employment of spring52.

Returning once again to FIG. 2A, a membrane compression screw 54 isthreaded perpendicularly through the wall of shaft 32 at about itsmidpoint. As may be seen through the cutaway portion of the shaft, theinterior wall 56 of shaft 32 is equipped with two protruding ridges 58.As will be described in greater detail, infra, compression screw 54 willbe used to urge the integumentary membrane between ridges 58 and againstinterior wall 56 to form a secondary air and water-tight seal of theenclosure.

The distal end 60 of shaft 32 is also threaded to receive end cap 62shown here in cross-section. Note that the distal edge 64 of shaft 60 isrounded for purposes which will be explained below. End cap 62 houses agasket 66 at the base of its interior walls for sealing purposes. Othermethods of ensuring a proper seal will be recognized by those skilled inthe art. An air evacuation port 68 is concentrically aligned withaperture 28 of platform 22 and is situate at the base of cap 62.Evacuation port 68 is sized to receive both port closure means 70,preferably in the form of a rubber plug, and evacuation tube 72. Again,a proper seal is ensured using second gasket 74 or other appropriatemeans.

Reference still being made to FIG. 2A, two remaining components of thesubject invention are depicted; namely an insulating/pressurecompensation lens adapter 76 and membrane adjustment ring 78. Each aredepicted in greater detail in FIGS. 4A and 4B to which attention shouldnow be directed.

Insulating/pressure compensation lens adapter 76 is optionally attachedto the existing lens system of video and camera equipment via threads80. Shown here in cross-sectional view, this lens adapter is comprisedof housing 82 which holds two lenses 84A and 84B in parallelrelationship. An air space 86 is created between each lens via lensgasket 88. The purpose of this lens configuration (separation) is toprovide an insulating barrier between the electronic equipment's ambienttemperature and that of the surrounding water in order to prevent lensfogging. Second and third gaskets 90 are placed on lens surfacesopposite those in contact with lens gasket 88 to assure proper seatingof the lenses within the housing and for sealing purposes. Note that thedistal edges 92 of housing 82 are tapered. The purpose of the taperingis to prevent tearing of the integumentary enclosure when tightenedabout the adapter housing. It is also important to note that the setbackdistance 94 between lens 84B and the distal edge 92 of housing 82 ispreferably 1/16 inch. Applicant has determined that such a setback isnecessary to avoid rubbing of the membrane against the lens surfaceduring the membrane application process described below, whilesimultaneously limiting the degree of membrane distortion when exposedto sub-atmospheric conditions such as are encountered when operating theequipment under water. Integumentary enclosure 10 is kept tightly inplace over lens adapter 76 using elastic membrane adjusting ring 78which is seated within groove 96 of housing 82. It should be appreciatedthat video or photographic distortion may be prevented by assuring atight, wrinkle-free fit of the membrane over lens adapter 76. Finally,to facilitate removal and repositioning of adjustment ring 78 withrespect to the lens adapter, tabs 98 may be incrementally spaced aboutthe perimeter of the ring. Alternatively, one continuous flange may beemployed for this purpose.

Method of Use

Reference is now made to FIGS. 5-9 for the purpose of describing theinvention's application to a common video camera for underwater use. Thefirst step will be to determine whether use of the optional lens adapter76 is necessary. This will usually depend on two factors; first, whetherthere is a significant temperature difference between water and air, andsecond, whether the video camera's own lens system is incapable ofpreventing membrane distortion under pressure. Answering either query inthe affirmative suggests that employment of the lens adapter isappropriate.

Next, the video camera is placed into the integumentary enclosure, topend first. The open end 12 of the enclosure is then threaded throughboth the platform's aperture 28 and tubular shaft 32 until it emergesfrom the distal end 60 of the shaft (FIG. 5). If the very thinintegument 10 begins to bunch together, guide wires 14 may be twistedtogether and fed through the shaft opening to facilitate the enclosure'spassage. Note that compression screw 54 should be unscrewed to theextent possible such that it does not interfere with the threadingprocess. Once the open end 12 of membrane 10 is completely through theshaft 32, the enclosure should be adjusted to the best fit possiblearound the video camera by removing slack and repositioning the cameraon the top surface 26 of platform 22.

Referring now to FIG. 6, once the bulk of slack has been removed, thedistal end 10A of the membrane should be removed from the main body 10Bof enclosure 10 by tearing along perforation 18. Distal end 10A,together with guide wires 14, may be discarded. The balance of the openend 12 should then be folded upward around the exterior of shaft 32.Additionally, membrane adjustment ring 78 may be placed around lensadapter 76 generally, and held within notch 96, in particular

Reference now being made to FIG. 7, the subject invention is ready forthe air evacuation procedure. Note at this stage that membrane slackover the lens (FIG. 6) has been removed. This is accomplished by gentlygrasping and lifting tabs 98 while pulling the membrane until smooth inappearance across the lens surface area. Note further that cap 62 hasbeen secured in place and that the entire length of color band 16remains visualized above the cap. Visualization of the entire length ofcolor band 16 assures that the enclosure is properly positioned to avoidleaks. Also note that evacuation tube 72 has been inserted throughevacuation port 68 and into the open end 12 of the enclosure 10.Finally, note that the video camera is properly positioned withinretaining walls 24.

Referring now to FIG. 8, it may be observed that enclosure 10 is closelyconformed to the contours of the video camera, thus forming a skin orintegument around same which not only protects the equipment from waterand the elements, but also provides uninhibited access to and operationof audio, video and infra-red components of the equipment. Conformity ofthe membrane to the equipment surface is accomplished by withdrawing airwithin the enclosure 10 through evacuation tube 72 either manually withthe mouth, or by mechanical means. Upon removal of air from the system,shaft 32 is rotated about platform 22 until ratchet head 50 (FIG. 2B)engages ratchet teeth 44. Thereafter, the shaft should be turned until apredesignated number of "clicks" is achieved. This number will have beenpredetermined and will depend on the number of ratchet teeth, thediameter of the shaft and other factors which will be obvious to onehaving reasonable skill in the art. The predetermined number of clicksshould be that number which causes membrane 10 to twist snugly aboutevacuation tube 72 such that it may be removed without tearing themembrane. Upon removal of evacuation tube 72, the twisted membrane willclose in on itself thereby creating an air and water-tight barrierbetween the equipment and its environment outside of the membrane. Theshaft may be further rotated to tighten the seal. Closure means 70should then be placed within evacuation port 68 to create the primaryseal of the system (FIG. 9).

As a final precaution, compression screw 54 is then tightened to forcethe twisted membrane between compression ridges 58 and against theinterior wall 56 of the shaft to create another secondary seal. Hereagain, caution should be exercised so as not to tear the membrane duringtightening. Securing means 102 may be used to secure the equipment toplatform 22. A simple elastic band or strap with conventional closuremeans is preferred.

Thusly configured, the subject apparatus and equipment therein are readyfor underwater use and in otherwise hostile environments such as on thebeach, in rain, snow, etcetera. It should be recognized that the subjectinvention is intended to provide a means for underwater use of equipmentat only moderate depths. The system is not intended for use a greaterdepths which require pressurization of the system. The subject systemis, however, adequate for use in conventional swimming pools and naturalbodies of water of similar depths.

Although the present invention has been described with reference to theparticular embodiments herein set forth, it is understood that thepresent disclosure has been made only by way of example and thatnumerous changes in details of construction may be resorted to withoutdeparting from the spirit and scope of the invention. Thus, the scope ofthe invention should not be limited by the foregoing specifications, butrather only by the scope of the claims appended hereto.

What is claimed as being new, useful and desired to be protected byLetters Patent of the United States is as follows:
 1. An integumentaryenclosure for electronic equipment, particularly video cameras,comprising:(a) an optically transparent membrane of bag-likeconfiguration for the reception of the electronic equipment; (b) asupport platform upon which the electronic equipment is secured for use;said platform being adapted with an aperture disposed through itscenter; (c) a tubular shaft having proximal and distal ends; saidproximal end being rotatably mounted to said platform and incommunication with said aperture of said platform such that an open endof said membrane may be inserted through said aperture and through saidshaft until it emerges from said distal end of said shaft; (d) membraneclosure means removably attached to said distal end of said shaft; and(e) air extraction means capable of slidable insertion into said shaftfor the removal of air within said membrane.
 2. An integumentaryenclosure for electronic equipment, particularly video cameras,comprising:(a) an optically transparent membrane of bag-likeconfiguration for the reception of the electronic equipment; (b) asupport platform upon which the electronic equipment is secured for use;said platform being adapted with an aperture disposed through itscenter; (c) a tubular shaft having proximal and distal ends; saidproximal end being rotatably mounted to said platform and incommunication with said aperture of said platform such that an open endof said membrane may be inserted through said aperture and through saidshaft until it emerges from said distal end of said shaft; (d) firstmembrane closure means removably attached to said distal end of saidshaft; (e) second membrane closure means disposed through said shaft;said second membrane closure means being comprised of a compressionscrew capable of closing said membrane by forcing same against theinterior wall of said shaft; and (f) air extraction means capable ofslidable insertion into said shaft for the removal of air within saidmembrane.
 3. A method of sealing electronic equipment within anintegumentary enclosure comprising the steps of:(a) inserting theelectronic equipment within an optically transparent membrane; (b)threading an open end of said membrane through an aperture disposedthrough the center of an electronic equipment support platform; (c)threading said open end of said membrane through a tubular shaft havingproximal and distal ends; said proximal end being rotatably mounted tosaid platform and in communication with said aperture of said platform;(d) permitting said open end of said membrane to emerge from the distalend of said shaft; (e) folding said open end of said membrane over theoutside of said distal end of said shaft; (f) inserting air evacuationmeans into said open end of said membrane; (g) withdrawing air throughsaid air evacuation means until said membrane closely conforms to thecontours of said electronic equipment; (h) closing said distal end ofsaid shaft with shaft closing means such that the open end of saidmembrane is closed to form an airtight and watertight seal.
 4. Theintegumentary enclosure of claim 1, further adapted with a ratchetassembly between said platform and said shaft such that said shaft iscapable of incremental rotation about said platform.
 5. Theintegumentary enclosure of claim 2, further adapted with a ratchetassembly between said platform and said shaft such that said shaft iscapable of incremental rotation about said platform.